Cross Fit – Is It Killing You??

Cross Fit Box jump
(Courtesy of



First of all, you need to understand the difference between aerobic and anaerobic exercise. Aerobic exercise requires oxygen, is low powered and lasts for greater than 15-20 minutes. Anaerobic exercise, like Cross Fit, does not require oxygen, is high powered and each exercise lasts less than 2 minutes.

The Positives: Recent studies have shown that anaerobic exercise is a vastly superior protocol for fat burning than it’s less intense aerobic counterpart. There is evidence that shows that anaerobic exercise is evenly matched to aerobic exercise with regard to cardiovascular benefits.  Check out the evidence in an article in the Journal of Strength and Conditioning. More evidence that comparable calorie burning effects can be achieved in half the time with anaerobic exercise.

The Negatives: Potential for INJURY! The article in the Journal of Strength and Conditioning also states that 16% of the participants dropped out due to “injury or overuse”. In addition, in 2011, the U.S. military, in conjunction with the American College of Sorts Medicine, advised soldiers to avoid CrossFit, citing “disproportionate musculo-skeletal injury risk.” You can read it HERE. In 2009, the US Military was encouraging training programs such as CrossFit. You can read it HERE. So what happened?

CrossFit goes out of its way to warn people that if they can’t maintain proper technique, they should back off. After all, the CrossFit mantra is “Mechanics, Consistency, Intensity”. Backing off , however, is a hard sell for many participants because workouts are viewed as a competition. The 2009 US Military study states that “Properly trained coaches are fundamentally important in both establishing an effective training program and developing proper movement mechanics in athletes.” It sounds like something, or someone, went wrong between 2009 and 2011.

So I guess the biggest question that you should ask (before joining a local Cross Fit gym) is WHO is running the classes and HOW they are trained. Make sure they at least have Level I or Level II Cross Fit training. A power lifting background is very helpful as power lifters are obsessive about proper form. Make sure you observe a class or two to witness how or if the instructor is scrutinizing and ensuring proper form. The proof is in the puddin’.